1. Field of the Invention
The present invention relates to a matte film or sheet. More particularly, the present invention relates to a matte film or sheet prepared from a specific polymeric blend. The matte film or sheet prepared by the specific method of the present invention has good matte properties, feel and flexibility; and is excellent in tensile modulus, laminating properties, impact resistance, and scratch resistance.
Further, the present invention relates to a matte film or sheet prepared from the polymeric blend which further comprises at least one of inorganic fillers and flame retardants. In this case, the matte film or sheet has further characteristics such as flame resistance, chalk resistance and covering power.
The matte films or sheets of the present invention can be widely used to fabricate various articles such as adhesive tapes, covers or cases for stationery, fashion bags, sheets for interior finish work in construction and automobile industries, and sheets for dressing steel plates.
2. Background Art
Until now, polyvinyl chloride (hereinafter also referred to as PVC) resins have been used for the preparation of matte films or sheets. Two main drawbacks of the PVC film or sheet are: 1) the blooming of plasticizer which can cause the deterioration of flexibility of the film or sheet; and 2) a large amount of HCl gas is evolved when subjected to combustion.
At present, such PVC matte films or sheets have been replaced by polyolefin-based films which have no such problem. Japanese Laid Open Publication No. 50-56451 discloses a process for preparing a polyolefin-based matte film or sheet prepared directly from a polyethylene having a specific melt flow rate (MFR) and a specific ratio of high-load MFR to low-load MFR by extruding or molding the polyethylene under specific conditions. Japanese Laid Open Publication No. 59-215343 discloses a process for blending an ethylene-vinylacetate copolymer resin (EVA) with a low-density ethylene-.alpha.-olefin copolymer (LLDPE). In this case, tensile modulus (a measure of the firmness of film), thermal resistance and covering power of the film or sheet are insufficient.
Further, Japanese Laid Open Publication No. H1-185306 discloses a copolymer of propylene with a vinyl trialkylsilane in an amount of the order of a few ppm. In this case, the films or sheets exhibit poor flexibility and covering power, although thermal resistance may be improved. Japanese Laid Open Publication No. H2-92944 describes a polypropylene-based matte sheet prepared from a polymeric blend of a polypropylene resin, a high-density super high-molecular weight polyethylene (HDPE), a super high-molecular weight elastomer, and an inorganic filler. According to the disclosure, tensile modulus, thermal resistance and covering power of the sheet are improved to some extent. However, the sheet still exhibits poor flame resistance, laminating properties, chalk and scratch resistance. Therefore, there is still a need for improvement in these poor properties.
U.S. Pat. No. 4,148,955 discloses a process for preparing a matte film by further blending glass balloon having an average particle diameter of 0.5 to 75 .mu.m. GB 1,453,649 proposes an improved process for preparing a composite matte film having both surface layers made of an ethylene-propylene block copolymer. Further, GB 1,581,686 proposes a process for preparing a matte film by calendaring a resin using a pair of rolls revolving at different circumferential speeds. In these cases, productivity is low, and tensile modulus, flexibility, laminating properties and impact resistance are insufficient.